Discrepancies Between Solute Transport Pathways Determined Using Hydraulic and Tracer Experimental Techniques

Accurate characterization of the transport pathways in fractured rock aquifers is a necessity in many fields of hydrogeology, including source water protection and contaminated site remediation.   Due to the high cost of characterization methods, it is standard practice to use only one characterization method in developing the conceptual model for a site.  

The objective of this study is to investigate a contaminated field site in Kingston, Ontario using constant head testing, pulse interference testing and three methods of tracer experimentation (radially divergent, natural gradient and dipole).  Three conceptual models of the site were created using the data generated from each characterization method.  A comprehensive conceptual model using the totality of the field data was produced and the separate conceptual models were compared and contrasted.

The comparison of the conceptual models produced by this process found that the conceptual model produced from the constant head testing predicted the greatest number of transsmissive solute transport pathways, followed by the pulse interference model and the tracer experimentation model respectively. The results from the three conceptual models produced significantly different representations of solute transport.  This has significant implications for the both the design of contaminated site characterization and the implementation of remediation programs.